The present invention relates to a vehicle-running control system for electronically controlling an engine, a transmission and a clutch.
A vehicle-running control system for electronically controlling an engine, a transmission and a clutch is known well. In the known system, Japanese Patent Application Laid-Open Nos. 61-1851 and 61-1852 disclose a technique in which when a malfunction occurs in an engine combustion control device, the malfunction is detected to stop or suspend combustion in the engine, thereby enhancing safety of the vehicle running.
Inconvenience occurs, however, in case where the vehicle-running control system disclosed in the above patents is applied to a vehicle having installed thereon a power steering device and/or a power brake device which are known well. Specifically, rotation of the engine, for example, is transmitted to the power steering device to actuate a hydraulic pump thereof such that hydraulic pressure obtained by the hydraulic pump is utilized as a power source for steering the vehicle. On the other hand, the power brake device employs its power source such as, for example, negative pressure or vacuum at an intake manifold connected to the engine, or compressed air pressure generated by a compressor to which the engine rotation is transmitted. When the combustion in the engine is suspended during an emergency rotation of an axle is not transmitted to the engine if the gear position of the transmission is a neutral or the clutch is in a disengaged position As a result, power used in the power steering device and/or the power brake device is reduced or weakened, resulting in a deterioration of maneuverability of the vehicle.